Animation of Dupliverts with Shape Keys with Python api
It is possible to keyframe each vertex. While by default Blender does not provide a GUI way to do this, it does include the AnimAll addon that provides a way to visually keyframe various components and values like vertices and edge creases. A python script can also easily keyframe the vertices.

import bpy
from random import random

obj = bpy.context.object
for f in range(bpy.context.scene.frame_end):
    for v in obj.data.vertices:
        m = random() * 0.1
        if f%2:
            v.co.z += m
        else:
            v.co.z -= m
        # index of 2 means only the z-axis
        # -1 (x,y, and z change), 0 x-axis, 1 y-axis
        # you will get weird behavior if the index and 
        # axis changed do not match
        v.keyframe_insert('co', index=2, frame=f)


Once keyframed they show in the graph editor and dopesheet like any other animation, meaning modifiers can be added and interpolation types changed. You will find the fcurves in obj.data.animation_data.action.fcurves.